Cloud Vulnerability DB
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Vulnerability DatabaseCVE-2021-4173
CVE-2021-4173:
NixOS vulnerability analysis and mitigation
Overview
CVE-2021-4173 is a use-after-free vulnerability affecting Vim text editor. The vulnerability was discovered in December 2021 and affects Vim versions prior to 8.2.3902. The issue occurs specifically with nested :def functions in Vim (CVE Mitre).
Technical details
The vulnerability is caused by a use-after-free condition when handling nested :def functions. The issue was addressed in patch 8.2.3902 by improving memory handling and adding validation to ensure cmdlinep remains valid. The fix involved modifying how linetofree is passed from compiledeffunction() and adding checks to verify cmdlinep validity (Github Commit).
Impact
A successful exploitation of this vulnerability could lead to unexpected application termination or potential arbitrary code execution in the context of the Vim application (Debian Tracker).
Mitigation and workarounds
The vulnerability has been fixed in Vim version 8.2.3902. Users are advised to upgrade to this version or later. The fix has been backported to various Linux distributions including Fedora, Debian, and Apple operating systems (Fedora Update, Apple Security).
Additional resources
Source: This report was generated using AI
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